Urborg, Tomb of Yawgmoth is a nonbasic land. You may put up to 4 of them into your constructed deck, but usually you do not want to because it is also a legendary land. If at any moment you control two or more Urborg, Tomb of Yawgmoth, you will have to choose one, then put all other into their owners’ graveyards. This rule is called the “legend rule”. The rule only affects lands with the exact same name; controling an Urborg and an Urborg, Tomb of Yawgmoth has no downside.
From this moment on, I shall refer to Urborg, Tomb of Yawgmoth simply as Urborg, to shorten it up.
Urborg has one static ability that functions while the land is on the battlefield. The effect of this ability impacts all lands on the battlefield, including Urborg itself. Urborg has no effect on land cards in the graveyard and library!
Now on to the key part:
How does Urborg’s ability function?
Urborg’s effect gives lands a basic land type — Swamp. Magic has a special rule for such occasions:
305.7. If an effect sets a land’s subtype to one or more of the basic land types, the land no longer has its old land type. It loses all abilities generated from its rules text, its old land types, and any copy effects affecting that land, and it gains the appropriate mana ability for each new basic land type. Note that this doesn’t remove any abilities that were granted to the land by other effects.
Setting a land’s subtype doesn’t add or remove any card types (such as creature) or supertypes (such as basic, legendary, and snow) the land may have.
If a land gains one or more land types in addition to its own, it keeps its land types and rules text, and it gains the new land types and mana abilities.
Последнее предложение правила как раз описывает способность Урборга, который даёт тип базовой земли в дополнение к существующим, а значит, не лишает землю предыдущих типов и каких-либо способностей:
Urborg’s best buddies
Urborg, Tomb of Yawgmoth and Blood Moon
When you face Magus of the Moon, take note that it is not enough to remove his abilities to disarm his effect:
An animated Urborg loses its abilities
Now let us compare the above situation with the following: we remove Urborg’s effect after it begins to apply. We shall get a different result:
Urborg and Commander (EDH)
It’s a holiday for all EDH lovers! Urborg may be played in all decks with any commander! It is colorless as the overwhelming majority of other lands, and besides, it has no mana abilities as very few other lands, which means it doesn’t have any colored mana symbols in its text! Rejoice!
Translated by Witas Spasovski